Problem: Express your answer as a mixed number simplified to lowest terms. $5\dfrac{3}{20}-3\dfrac{1}{4} = {?}$
Answer: Find a common denominator for the fractions: $= {5\dfrac{3}{20}}-{3\dfrac{5}{20}}$ Convert ${5\dfrac{3}{20}}$ to ${4 + \dfrac{20}{20} + \dfrac{3}{20}}$ So the problem becomes: ${4\dfrac{23}{20}}-{3\dfrac{5}{20}}$ Separate the whole numbers from the fractional parts: $= {4} + {\dfrac{23}{20}} - {3} - {\dfrac{5}{20}}$ Bring the whole numbers together and the fractions together: $= {4} - {3} + {\dfrac{23}{20}} - {\dfrac{5}{20}}$ Subtract the whole numbers: $=1 + {\dfrac{23}{20}} - {\dfrac{5}{20}}$ Subtract the fractions: $= 1+\dfrac{18}{20}$ Combine the whole and fractional parts into a mixed number: $= 1\dfrac{18}{20}$ Simplify to lowest terms: $= 1\dfrac{9}{10}$